AC Maintenance Checklist: What to Do Monthly, Quarterly, Yearly

Professional tune-ups happen once or twice a year. In between, there's stuff you can do that meaningfully extends your system's life. Here's the honest, homeowner-doable checklist.

Monthly (May–October)

• Check the 1" filter — replace if you can't easily see through it against a light
• Walk around the outdoor unit — clear cottonwood, oleander leaves, palm fronds, wind-blown trash
• Note anything unusual: louder-than-normal cycling, warmer supply air, longer run times, humidity spike

Monthly (November–April)

• Check filter (less critical off-season, but do it)
• Test thermostat mode — cool → heat → cool ensures the reversing valve on a heat pump is exercising

Quarterly

• Gently rinse the outdoor coil with a garden hose (from inside out if you can access; from outside in if not). Water only. No pressure washer.
• Confirm supply and return registers are open and unobstructed by furniture
• Wipe down thermostat and check batteries if applicable

Annually

• Professional tune-up (see what's actually included)
• Verify your carbon-monoxide detector works (test button + battery)
• Confirm smoke detectors work
• Photograph your equipment nameplate for warranty records

Every 5 years

• Duct blaster / airflow assessment — catches degraded duct sealing
• Insulation assessment — attic settling and rodent damage accumulate

Things NOT to DIY

• Refrigerant charging — requires EPA certification and specialized gauges
• Compressor or capacitor replacement — 240V hazard, specialized parts
• Electrical work at the disconnect or panel
• Duct sealing inside plenums — mastic and Aerosolized DuctSeal is professional-tool territory
• Gas furnace burner cleaning — combustion analysis required to verify safety after

Warning signs to call about immediately

• Ice on the copper refrigerant line
• Water where there shouldn't be water (attic drip pan overflowing, ceiling stain)
• Burning-plastic smell (electrical short — kill the breaker)
• Any gas odor
• CO detector activation

Keep this list on your fridge or in your calendar. Ten minutes a month prevents most major repair bills. Book your next tune-up anytime — or lock in twice-yearly with an Absolute Comfort Plan.